55181990 has 16 divisors (see below), whose sum is σ = 99515952. Its totient is φ = 22030944.

The previous prime is 55181939. The next prime is 55181999. The reversal of 55181990 is 9918155.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55181999) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 617 + ... + 10523.

It is an arithmetic number, because the mean of its divisors is an integer number (6219747).

Almost surely, 2^55181990 is an apocalyptic number.

55181990 is a deficient number, since it is larger than the sum of its proper divisors (44333962).

55181990 is a wasteful number, since it uses less digits than its factorization.

55181990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10471.

The product of its (nonzero) digits is 16200, while the sum is 38.

The square root of 55181990 is about 7428.4581172677. The cubic root of 55181990 is about 380.7142384119.

The spelling of 55181990 in words is "fifty-five million, one hundred eighty-one thousand, nine hundred ninety".